Radiators with plastic pipe from behind

[asadm]

Hi All,

I am DIY'er planning to lay my F&R as a 22mm copper "trunk" which will then drop down to feed individual radiators. I would like to drop down (in wall chase) with 15mm copper which present themselves behind the rads and then connect flexible plastic pipe (15 or 10mm) which attaches to the radiator valves. I've seen this configuration in new builds.

Is this possible? Specifically, will I have enough room behind the rad to connect copper to plastic? I have had a suggestion to drop down from the 22mm into 10mm plastic (i.e. not use 15mm copper at all) which goes all the way to the valves but I would prefer to come down with 15mm copper as close to the rads as possible if this is feasible.

I look forward to your advice.

 

[Rybo_1]

If you're going to come down the wall in 15mm copper you may as well take it all the way to the valve as well

 

[asadm]

using the plastic would provide me with some flexibility as otherwise the copper needs to be precisely cut to fit into the valves. Aesthetically, I prefer the plastic pipe on show slightly rather than the copper.
I could really do with some advice on how I achieve this particular configuration. Thanks for your help.

 

[ShaunCorbs]

using the plastic would provide me with some flexibility as otherwise the copper needs to be precisely cut to fit into the valves. Aesthetically, I prefer the plastic pipe on show slightly rather than the copper.
I could really do with some advice on how I achieve this particular configuration. Thanks for your help.

15mm plastic then

 

[asadm]

Thanks for the prompt response. If I came down the wall chase with 15mm plastic off the 22mm copper, would this be flexible enough to connect to the radiator valves (from behind as I described)? If yes, this would be my preferred choice I think...

 

[Best]

Copper 15mm with a little bend on the end out to bring it in line for a soldered elbow up to the rad valve. Lovely neat and professional looking.

 

[ShaunCorbs]

Thanks for the prompt response. If I came down the wall chase with 15mm plastic off the 22mm copper, would this be flexible enough to connect to the radiator valves (from behind as I described)? If yes, this would be my preferred choice I think...

it would be ok on a big rad but a bit harder on a small rad

 

[ShaunCorbs]

Copper 15mm with a little bend on the end out to bring it in line for a soldered elbow up to the rad valve. Lovely neat and professional looking.

dont think he can solder

 

[asadm]

That would look nice but given the primacy of my skills, I don't think I'm up to that level of precision yet
But also, I do like the appearance of plastic tube which then disappears behind the radiator instead of having the copper on show.

 

[Best]

Thanks for the prompt response. If I came down the wall chase with 15mm plastic off the 22mm copper, would this be flexible enough to connect to the radiator valves (from behind as I described)? If yes, this would be my preferred choice I think...

No. I don't use plastic, but I know it isn't very flexible. Better you keep the bits on show in rigid pipe - in other words copper IMO.
Although I must admit if I had to do it a DIY way, but nice and easy and good enough, I would say 10 mm plastic to valves

 

[asadm]

With the smaller rads (most of mine are at least 1.5 metres wide) could I reduce the 15mm plastic coming down the chase to 10mm as it comes out of the wall to give me the additional flexibility?
I will go with the 15mm plastic down from the 22mm copper, all the way to the rads with all other rads

 

[Best]

That would look nice but given the primacy of my skills, I don't think I'm up to that level of precision yet
But also, I do like the appearance of plastic tube which then disappears behind the radiator instead of having the copper on show.

But copper can disappear behind rads just the same as plastic can. Also copper won't go all shapes when heated. Fair enough if you aren't confident to use copper you are probably very wise to not go with it

 

[asadm]

Thanks for all the help guys. Do we have a consensus on all the larger rads (1.5m wide +) being fed by a 15mm plastic pipe which comes off a 22mm copper. The 15mm will come down the wall chase; out from behind the rad and then connect to the valves. Does this have your blessings?
With the smaller rads, I need to do some improvisation b the sounds of it

 

[ShaunCorbs]

sounds ok but dont forget to add a metal protection plate just incase

 

[Best]

With the smaller rads (most of mine are at least 1.5 metres wide) could I reduce the 15mm plastic coming down the chase to 10mm as it comes out of the wall to give me the additional flexibility?
I will go with the 15mm plastic down from the 22mm copper, all the way to the rads with all other rads

How are you going to do the plastic 10mm neatly? It will need supported by clips or trunking.
To run down the wall with 15mm and then using a 15x10 mm fitting change over to 10mm will then shorten the restrictive length of the pipe, so will work well.

 

[asadm]

Is this the plate that acts as the outlet plate? i.e. where the pipe exits the wall?

 

[ShaunCorbs]

Is this the plate that acts as the outlet plate? i.e. where the pipe exits the wall?

no saves increase of pitting a nail though and also acts like a locater strip

 

[asadm]

@Best, I was envisaging that the 15mm pipe that will come down the wall chase and yes, I will clip this before plasterboarding and making good, will then come out of the wall and snugly fit to the radiator valve. This will have the effect, of very little plastic pipe being on show as most of it will be behind the radiator. I wasn't planning to drop to 10mm. Am I missing something?

 

[asadm]

@ShornCobs, got it! Do you also recommend an outlet plate and if so what should I be using?

 

[ShaunCorbs]

@ShornCobs, got it! Do you also recommend an outlet plate and if so what should I be using?

yes and not an elec back box you can get special ones for plastic pipe

 

[asadm]

Cool. Final question (promise!) Which 15mm plastic pipe do you recommend for this purpose? I've seen several different type...

 

[ShaunCorbs]

Cool. Final question (promise!) Which 15mm plastic pipe do you recommend for this purpose? I've seen several different type...

not the cheapest jg, uponor, hep20

 

[asadm]

Guys, i'm struggling to locate radiator pipe outlet plates for the 15mm plastic I am planning to use. They all appear to cater for 10mm pipe. Any suggestions?

 

[Norcs]

15mm Yorkshire mlcp is the answer when copper and plastic don't meet the specifications.
Very easy worked with. I pulled this stuff through the center of the studding on a loft conversion I'm doing at the moment round corners and the final corner out to the shower valve and not a single concealed joint.

Both copper and plastic just wouldn't work.

 

[Norcs]

You don't have the bending radius with plastic and copper cannot be threaded. Unless its soft drawn. Mlcp is the closest you'll get to soft drawn copper.
Soft drawn copper is available yet you never hear it being mentioned by plumbers.

 

[Sparkgap]

I'd recommend going for smallbore copper off the 22mm down to each rad (depends on what the radiator outputs are) instead of faffing around going 22/15/plastic. Some of my rads are 8mm plastic, others 8 or 10mm copper. Prefer the copper as its stronger and easier to alter/extend.